Process for making blends of polyolefin and poly(ethylene oxide)

ABSTRACT

A compositional blend having from about 1 weight percent to about 85 weight percent of a modified polyolefin and from about 99 weight percent to about 15 weight percent of modified poly(ethylene oxide). The modified polyolefin and modified poly(ethylene oxide) have a total of from about 1 weight percent to about 30 weight percent of a monomer grafted thereto. Included is a method for making the blend comprising using a single pass extruder to perform the steps of melt blending the polyolefin, poly(ethylene oxide), the monomer and a sufficient amount free radical initiator to graft from about 1 percent to 100 percent of the monomer onto the polyolefin and poly(ethylene oxide).

This is a continuation of application Ser. No. 08/777,226 filed Dec. 31,1996, now U.S. Pat. No. 5,700,872, entitled "BLENDS OF POLYOLEFIN ANDPOLY(ETHYLENE OXIDE) AND PROCESS FOR MAKING THE BLENDS". The entiredisclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to blends of polyolefin and poly(ethyleneoxide) and a method of making the blends. More particularly, theinvention relates to blends having up to about 85 weight percent of amodified polyethylene or modified polypropylene and a modifiedpoly(ethylene oxide) and a method of making the modified polyolefin andmodified poly(ethylene oxide) blend using a single step reactiveextruder.

BACKGROUND OF THE INVENTION

Personal care products, such as, diapers, sanitary napkins, adultincontinence garments, and the like are generally constructed from anumber of different components and materials. Such articles typicallyhave a portion, usually the backing layer, liner, or baffle constructedof a liquid repellent film material. This repellent material isappropriately constructed to minimize or prevent the exudation of theabsorbed liquid from the article and to obtain greater utilization ofthe absorbent capacity of the product. The liquid repellent filmcommonly used includes plastic materials such as polyethylene films andthe like.

Although such products are relatively inexpensive, sanitary and easy touse disposal of a product once soiled is not without its problems. Withgreater interest being placed in protecting the environment today, thereis a need to develop materials that are more compatible with theexisting and developing waste disposal technologies while stilldelivering performance consumers have come to expect. An ideal disposalalternative would be to use municipal sewage treatment and privateresidential septic systems. Products suited for disposal in sewagesystems can be flushed down a convenient toilet and are termed"flushable." While flushing such articles would be convenient, theliquid repellent material which normally does not disintegrate in watertends to plug toilets and sewer pipes. It therefore becomes necessary,although undesirable, to separate the barrier film material from theabsorbent article prior to flushing.

In addition to the article itself, typically the packaging in which thedisposable article is distributed is also made from a water resistantmaterial. Water resistivity is necessary to prevent the degradation ofthe packaging from environmental conditions and to protect thedisposable articles therein. Although this packaging may be safelystored with other refuse for commercial disposal, and especially in thecase of individual packaging of the products, it is often moreconvenient to dispose of the packaging in the toilet with the discardeddisposable article. However, in the cases where such packaging iscomposed of a water resistant material, plugging of the drains to thetoilet typically results.

In an effort to overcome these deficiencies, two methodologies have beenutilized. The first is for hydrophilic materials to be treated with ahydrophobic material to impart the desired water resistant properties tothe material.

The second method has been to modify a water resistant polymer. One ofthe more useful ways of modifying polymers involves blending them withother polymers of different structures and properties. In a few cases,polymer blend combinations are thermodynamically miscible and exhibitphysical and mechanical compatibility. However, by far a greater numberof blends are phase separated and generally exhibit poor mechanicalcompatibility. Phase separated blends can in some cases exhibit physicaland mechanical compatibility where the polymer compositions are similar,for example, polyolefin blended with other similar polyolefins, or whereinterfacial agents are added to improve the compatibility at theinterface between the constituents of the polymer blend.

Polymer blends of polyolefins and poly(ethylene oxide) are meltprocessible but exhibit very poor mechanical compatibility. This poormechanical compatibility is manifested in the mechanical propertyprofile of the blends relative to the properties of the unblendedconstituents.

In view of the problems of the prior art, it remains highly desirable toprovide a water responsive material. Such blends could be used formaking flushable barrier films, extrusion applications and injectedmolded articles.

SUMMARY OF THE INVENTION

Briefly, one aspect of the present invention provides for a modifiedpolyolefin and modified poly(ethylene oxide) blend composition. Theblend composition is composed of from about 1 weight percent to about 85weight percent of a modified polyolefin and from about 99 weight percentto about 15 weight percent of a modified poly(ethylene oxide). Themodified polyolefin and modified poly(ethylene oxide) have graftedthereto from about 1 weight percent to about 30 weight percent, based onthe weight of the polyolefin and poly(ethylene oxide), of a monomer.

Another aspect of the invention provides for a method of making themodified polyolefin and modified poly(ethylene oxide) blend composition.The method provides a single pass, melt reactive extrusion modificationof the polyolefin and poly(ethylene oxide). This single step processaffords significant advantages over a two step process where thepolyolefin is first modified by grafting a monomer onto the polyolefinbackbone which is then re-extruded with the poly(ethylene oxide). A fewof the advantages include cost savings, reduced polymer degradation andgreater uniformity in the final product. Specifically, the method ofpreparing the blend of modified polyolefin and modified poly(ethyleneoxide) using a single pass, melt reactive extruder comprises melting thepolyolefin and poly(ethylene oxide) in the extruder and adding to thepolyolefin and poly(ethylene oxide) blend a monomer and a sufficientamount of a free radical initiator to graft from about 1 weight percentto about 100 weight percent of the monomer onto the polyolefin andpoly(ethylene oxide).

It is an object of the invention to provide a blend compositioncomprising a modified polyolefin and modified poly(ethylene oxide). Morespecifically, it is an object of the invention to provide a blendcomposition comprising a modified polyethylene or modified polypropyleneand modified poly(ethylene oxide).

Another object of the invention is to provide a method of making amodified polyolefin and modified poly(ethylene oxide) blend compositionusing a single pass reactive extruder.

As used herein "reactive extrusion" is the use of chemical reactionsduring polymer extrusion to form desired products. Free radicalinitiator, crosslinking agents, and other reactive additives can beinjected into the extruder to cause such reactions.

DETAILED DESCRIPTION OF THE INVENTION

The mechanical and visual compatibility of blends of polyolefins andpoly(ethylene oxide) is very poor. However, it has now unexpectedly beenfound that polyolefins and poly(ethylene oxide) can be modified with oneor more monomers, such that materials made from blends having upwards ofabout 85 weight percent of a modified polyolefin and as little as 15weight percent of a modified poly(ethylene oxide) are water responsive.More specifically, it has been found that blends of polyolefins andpoly(ethylene oxide), when grafted with a monomer during reactiveextrusion imparts water responsiveness to films and thermoplasticarticles made therefrom. Accordingly, one aspect of the invention is fora composition of matter comprising a polymer blend having from about 1weight percent to about 85 weight percent of a modified polyolefin andfrom about 99 weight percent to about 15 weight percent of a modifiedpoly(ethylene oxide). Preferably, the blend comprises from about 30weight percent to about 85 weight percent of a modified polyolefin andfrom about 70 weight percent to about 15 weight percent of modifiedpoly(ethylene oxide). More preferably, the blend comprises from about 55weight percent to about 85 weight percent of a modified polyolefin andfrom about 45 weight percent to about 15 weight percent of modifiedpoly(ethylene oxide).

The amount of monomer added to the blend of polyolefin and poly(ethyleneoxide) is from about 1 weight percent to about 30 weight percent,preferably, from about 1 weight percent to about 20 weight percent andmore preferably, from about 1 weight percent to about 10 weight percentwherein all such ranges are based on the total weight of the polyolefinand poly(ethylene oxide).

The saturated ethylene polymers useful in the practice of this inventionare homopolymers or copolymers of ethylene and polypropylene and areessentially linear in structure. As used herein, the term "saturated"refers to polymers which are fully saturated, but also includes polymerscontaining up to about 5% unsaturation. The homopolymers of ethyleneinclude those prepared under either low pressure, i.e., linear lowdensity or high density polyethylene, or high pressure, i.e., branchedor low density polyethylene. The high density polyethylenes aregenerally characterized by a density that is about equal to or greaterthan 0.94 grams per cubic centimeter (g/cc). Generally, the high densitypolyethylenes useful as the base resin in the present invention have adensity ranging from about 0.94 g/cc to about 0.97 g/cc. Thepolyethylenes can have a melt index, as measured at 2.16 kg and 190° C.,ranging from about 0.005 decigrams per minute (dg/min) to 100 dg/min.Desirably, the polyethylene has a melt index of 0.01 dg/min to about 50dg/min and more desirably of 0.05 dg/min to about 25 dg/min.Alternatively, mixtures of polyethylene can be used as the base resin inproducing the graft copolymer compositions, and such mixtures can have amelt index greater than 0.005 dg/min to less than about 100 dg/min.

The low density polyethylene has a density of less than 0.94 g/cc andare usually in the range of 0.91 g/cc to about 0.93 g/cc. The lowdensity polyethylene polymer has a melt index ranging from about 0.05dg/min to about 100 dg/min and desirably from 0.05 dg/min to about 20dg/min. Ultra low density polyethylene can be used in accordance withthe present invention. Generally, ultra low density polyethylene has adensity of less than 0.90 g/cc.

Generally, polypropylene has a semi-crystalline structure having amolecular weight of about 40,000 or more, a density of about 0.90 g/cc,a melting point of 168° to 171° C. for isotactic polypropylene and atensile strength of 5000 psi. Polypropylene can also have othertacticities including syndiotactic and atactic.

The above polyolefins can also be manufactured by using the well knownmultiple-site Ziegler-Natta catalysts or the more recent single-sitemetallocene catalysts. The metallocene catalyzed polyolefins have bettercontrolled polymer microstructures than polyolefins manufactured usingZiegler-Natta catalysts, including narrower molecular weightdistribution, well controlled chemical composition distribution,co-monomer sequence length distribution, and stereoregularity.Metallocene catalysts are known to polymerize propylene into atactic,isotactic, syndiotactic, isotactic-atactic steroblock copolymer.

Copolymers of ethylene which can be useful in the present invention mayinclude copolymers of ethylene with one or more additionalpolymerizable, unsaturated monomers. Examples of such copolymersinclude, but are not limited to, copolymers of ethylene and alphaolefins (such as propylene, butene, hexene or octene) including linearlow density polyethylene, copolymers of ethylene and vinyl esters oflinear or branched carboxylic acids having 1-24 carbon atoms such asethylene-vinyl acetate copolymers, and copolymers of ethylene andacrylic or methacrylic esters of linear, branched or cyclic alkanolshaving 1-28 carbon atoms. Examples of these latter copolymers includeethylene-alkyl (meth)acrylate copolymers, such as ethylene-methylacrylate copolymers.

The free radical initiators useful in the practice of this inventioninclude acyl peroxides such as benzoyl peroxide; dialkyl; diaryl; oraralkyl peroxides such as di-t-butyl peroxide; dicumyl peroxide; cumylbutyl peroxide; 1, 1-di-t-butyl peroxy-3, 5,5-trimethylcyclohexane; 2,5-dimethyl-2, 5-di(t-butylperoxy) hexane;2,5-dimethyl-2,5-bis(t-butylperoxy) hexyne-3 and bis(a-t-butylperoxyisopropylbenzene); peroxyesters such as t-butyl peroxypivalate;t-butyl peroctoate; t-butyl perbenzoate;2,5-dimethylhexyl-2,5-di(perbenzoate); t-butyl di(perphthalate); dialkylperoxymonocarbonates and peroxydicarbonates; hydroperoxides such ast-butyl hydroperoxide, p-methane hydroperoxide, pinane hydroperoxide andcumene hydroperoxide and ketone peroxides such as cyclohexanone peroxideand methyl ethyl ketone peroxide. Azo compounds such asazobisisobutyronitrile may also be used.

Poly(ethylene oxide) polymers suitable for the present invention canhave a molecular weight ranging from 100,000 to 8,000,000. Poly(ethyleneoxide) is available from Union Carbide Corporation under the trade nameof POLYOX®. Typically, poly(ethylene oxide) is a dry free flowing whitepowder having a crystalline melting point in the order of about 65° C.,above which poly(ethylene oxide) resin becomes thermoplastic and can beformed by molding, extrusion and other methods known in the art.

The method of making the polymer blends includes melt blending thedesired weight ratios of a mixture of the polyolefin, poly(ethyleneoxide), the monomer and a free radical initiator in an extruder and at areaction temperature where the polyolefin and poly(ethylene oxide) areconverted to a molten state. Accordingly, the polyolefin, poly(ethyleneoxide), monomer and free radical initiator can be simultaneously addedto the extruder before the polymer constituents, i.e., the polyolefinand poly(ethylene oxide) have been melted. The preferred monomers usedin the present invention are 2-hydroxyethyl methacrylate andpolyethylene glycol ethyl ether (meth)acrylate, both are available fromAldrich Chemical Company, Milwaukee, Wis. Preferably, the melt extruderused for melt blending can introduce various constituents into the blendat different locations along the screw length. For example, the freeradical initiator, crosslinking agents, or other reactive additives canbe injected into the blend before or after one or more of the polymerconstituents is melted or thoroughly mixed. More preferably, thepolyolefin and poly(ethylene oxide) are added at the beginning of theextruder. After melting, the monomer is added to melted polymers andfurther down the extruder barrel, the free radical initiator is fed tothe melt blend. Although not preferred the scope of the invention wouldinclude simultaneously adding the monomer and free radical initiatorinto the molten blend of polyolefin and poly(ethylene oxide). It isimportant to the method of the invention that the polyolefin andpoly(ethylene oxide) be melt blended contemporaneously with or beforethe addition of the monomer and free radical initiator. Although not tobe bound by any theory, it is believed that the monomer, in the presenceof the free radical initiator, grafts onto both the polyolefin andpoly(ethylene oxide) thereby allowing articles made from the blend ofmodified polyolefin and modified poly(ethylene oxide) to have a greaterwater responsiveness. As used herein the term "water responsiveness"refers to a loss of tensile strength or strain-to-break of a wet filmrelative to the dry film tensile strength or strain-to-break.

The amount of free radical initiator added to the extruder should be anamount sufficient to graft from about 1 percent to 100 percent of themonomer onto the polyolefin and poly(ethylene oxide). This can rangefrom about 0.1 weight percent to about 10 weight percent of initiator.Preferably, the amount of initiator added to the extruder ranges fromabout 0.1 weight percent to about 5 weight percent wherein all suchranges are based on the amount of monomer added to the melt blend.

Surprisingly, a film or other thermoplastic article made from themodified polyolefin and modified poly(ethylene oxide) blend describedabove is water responsive.

The present invention is illustrated in greater detail by the specificexamples presented below. It is to be understood that these examples areillustrative embodiments and are not intended to be limiting of theinvention, but rather are to be construed broadly within the scope andcontent of the appended claims.

In each of the Examples which follow a polyolefin/poly(ethylene oxide)blend was prepared as described. Comparative Example A is a physicalblend of the polymer resins. The blends of Comparative Examples B-D wereprepared by a two-step process. In the first step the polyethylene wasmodified by grafting a monomer thereto. The method of making themodified polyethylene is described in greater detail in the copendingU.S. patent application having U.S. Ser. No. 08/733,410 filed on Oct.18, 1996 the entire disclosure of which is incorporated herein byreference. In the second step the modified polyolefin is blended withthe poly(ethylene oxide). Select properties of these materials are inTable 1 below. Examples 1-4, 5-8 and 9-10 were made in accordance withthe present invention. Select properties of these materials are inTables 2, 3 and 4 respectively.

COMPARATIVE EXAMPLE A

A 60/40 weight percent resin blend of low density polyethylene having amelt index of 1.9 decigrams per minute (dg/min) and a density of 0.917grams per cubic centimeter (g/cc) (Dow 503I; available from Dow ChemicalCompany, Midland, Mich.) and poly(ethylene oxide) having a molecularweight of 200,000 g/mol. (POLYOX®WSRN-80 available from Union CarbideCorp.) were fed to a Haake counter-rotating twin screw extruder at arate of 5 pounds per hour (lb/hr). The extruder had a length of 300millimeters. Each conical screw had 30 millimeters diameter at the feedport and a diameter of 20 millimeters at the die. The extruder had fourheating zones set at 170, 180, 180 and 190 degrees Centigrade (C). Thescrew speed of the extruder was 150 rpm.

COMPARATIVE EXAMPLES B-D

For Comparative Examples B-D the low density polyethylene, Dow 503I, wasmodified by grafting thereto polyethylene glycol ethyl ethermethacrylate (PEG-MA; available from Aldrich Chemical Company,Milwaukee, Wis.). The PEG-MA grafted polyethylene was prepared using theHaake counter-rotating twin screw extruder described above. The feed tothe extruder comprised contemporaneously adding, at the extruder feedthroat, 5 lb/hr of polyethylene and the specified amounts of PEG-MA andfree radical initiator ((2, 5-dimethyl-2, 5-di(t-butylperoxy) hexane,supplied by Atochem, 2000 Market St. Philadelphia, Pa. under thetradename of LUPERSOL 101).

For Comparative Example B the PEG-MA feed rate was 0.125 lb/hr and theinitiator rate was 0.0125 lb/hr.

For Comparative Example C the PEG-MA feed rate was 0.25 lb/hr and theinitiator rate was 0.025 lb/hr.

For Comparative Example D the PEG-MA feed rate was 0.5 lb/hr and theinitiator rate was 0.025 lb/hr.

A 60/40 blend was prepared following the method of Comparative Example Aabove, except the modified polyethylene of each example was substitutedfor the unmodified polyethylene. The resulting products had thecharacteristics indicated in Table 1.

Film processing of the blends was performed using the Haake extruder asdescribed above with the following modifications. The extruder includeda 4 inch slit die at a temperature of 195 degrees C. The screw speed wasat 30 rpm. A chilled wind-up roll was used to collect the film. Thechilled roll was operated at a speed sufficient to form a film having athickness of about 4 mils (0.004 of an inch) and was maintained at atemperature of about 15-20 degrees C.

Dry and Wet Tensile Tests

Dry tensile tests were performed on a Sintech 1/D tensile testeravailable from MTS Systems Corp., Machesny Park, Ill. The film was cutinto a type V dogbone shape in accordance with ASTM D638. The test wasperformed with a grip separation of 30 millimeters and a crosshead speedof 4 millimeters/second.

Wet tensile tests were performed on a Vitodyne V1000 mini-tensile testeravailable from Chatillon, Greensboro, N.C. The film samples were placedin the grippers and submerged in ambient temperature, non-stirred waterfor 30 seconds. Peak stress, percent strain to break, energy to break(as area under stress versus strain curve), and modulus were calculatedfor each film tested and the percent loss in tensile properties from dryto wet was determined.

                  TABLE 1                                                         ______________________________________                                               #A      #B        #C        #D                                         Example #-                                                                             dry    wet    dry  wet  dry  wet  dry  wet                           ______________________________________                                        Thickness (mil)                                                                        4.5    4.4    4.5  4.5  4.0  4.0  5.0  5.0                           % Strain 390    390    330  110  320  70   170  30                            Peak Stress -                                                                          15.3   12.8   13.8 7.0  11.4 4.9  12.2 3.1                           (MPa)                                                                         Energy-break                                                                           42.2   41.5   32.7 6.7  27.6 2.4  16.5 0.5                           (x10.sup.6 J/m.sup.3)                                                         Modulus (MPa)                                                                          181    96.5   117.8                                                                              74.4 103.7                                                                              56.3 119.4                                                                              39.4                          ______________________________________                                        % Loss from Dry to Wet                                                        ______________________________________                                        % Strain       0%    65%        79%  82%                                      Peak Stress   16%    49%        57%  75%                                      Energy to Break                                                                              2%    80%        91%  97%                                      Modulus       47%    37%        46%  33%                                      ______________________________________                                    

EXAMPLES 1-4

The 60/40 weight percent resin blend of low density polyethylene (Dow503I) and poly(ethylene oxide) (WSRN-80) was fed to the Haakecounter-rotating twin screw extruder at a rate of 5 lb/hr.Contemporaneously with the polymer feed to the extruder, specifiedamounts of the monomer, PEG-MA, and free radical initiator (LUPERSOL101) were added at the feed throat. The extruder had four heating zonesset at 170, 180, 180 and 190 degrees C. The screw speed of the extruderwas 150 rpm.

For Example 1 the PEG-MA feed rate was 0.125 lb/hr and the initiatorrate was 0.0125 lb/hr.

For Example 2 the PEG-MA feed rate was 0.25 lb/hr and the initiator ratewas 0.025 lb/hr.

For Example 3 the PEG-MA feed rate was 0.5 lb/hr and the initiator ratewas 0.025 lb/hr.

For Example 4 the PEG-MA feed rate was 0.75 lb/hr and the initiator ratewas 0.0375 lb/hr.

The resulting products of Examples 1-4 had the characteristics indicatedin Table 2.

                  TABLE 2                                                         ______________________________________                                               #1      #2        #3        #4                                         Example #-                                                                             dry    wet    dry  wet  dry  wet  dry  wet                           ______________________________________                                        Thickness (mil)                                                                        4.4    4.4    5.6  5.5  4.2  4.2  4.9  4.6                           % Strain 400    70     280  50   590  90   250  50                            Peak Stress -                                                                          9.3    3.7    8.3  3.1  9.2  3.5  5.2  1.3                           (MPa)                                                                         Energy-break                                                                           30.6   1.7    18.1 0.9  46.8 2.0  9.8  0.3                           (x10.sup.6 J/m.sup.3)                                                         Modulus (MPa)                                                                          90.1   41.9   91.2 32.7 86.2 38.0 64.4 14.5                          ______________________________________                                        % Loss from Dry to Wet                                                        ______________________________________                                        % Strain      83%    83%        85%  81%                                      Peak Stress   60%    63%        62%  75%                                      Energy to Break                                                                             94%    95%        96%  97%                                      Modulus       53%    64%        56%  77%                                      ______________________________________                                    

For Examples 1-4 the amount of monomer grafted to polyethylene was 0.65weight percent, 1.03 weight percent, 0.51 weight percent and 1.13 weightpercent, respectively. The weight percent of monomer grafted to thepolyethylene was determined by FT-IR and elemental oxygen content asdescribed in copending U.S. patent application Ser. No. 08/733,410 filedOct. 18, 1996 the entire disclosure of which is incorporated herein byreference. For Example 3 the amount of monomer grafted to thepoly(ethylene oxide) was determined to be 14.9 weight percent by protonNMR spectroscopy.

EXAMPLES 5-8

The 60/40 weight percent resin blend of low density polyethylene (Dow503I) and poly(ethylene oxide) (WSRN-80) was fed to the Haakecounter-rotating twin screw extruder at a rate of 5 lb/hr.Contemporaneously with the polymer feed to the extruder, specifiedamounts of a monomer, 2-hydroxyethyl methacrylate, and free radicalinitiator (LUPERSOL 101) were added at the feed throat. The extruder hadfour heating zones set at 170, 180, 180 and 190 degrees C. The screwspeed of the extruder was 150 rpm.

For Example 5 the 2-hydroxyethyl methacrylate feed rate was 0.125 lb/hrand the initiator rate was 0.0125 lb/hr.

For Example 6 the 2- hydroxyethyl methacrylate feed rate was 0.25 lb/hrand the initiator rate was 0.025 lb/hr.

For Example 7 the 2- hydroxyethyl methacrylate feed rate was 0.5 lb/hrand the initiator rate was 0.025 lb/hr.

For Example 8 the 2- hydroxyethyl methacrylate feed rate was 0.75 lb/hrand the initiator rate was 0.0375 lb/hr.

The resulting products of Examples 5-8 had the characteristics indicatedin Table 3.

                  TABLE 3                                                         ______________________________________                                               #5      #6        #7        #8                                         Example #-                                                                             dry    wet    dry  wet  dry  wet  dry  wet                           ______________________________________                                        Thickness (mil)                                                                        4.5    4.6    4.2  4.7  4.5  4.5  5.0  4.6                           % Strain 350    50     390  40   420  40   350  30                            Peak Stress -                                                                          13.3   3.3    9.0  1.5  10.3 2.4  8.7  1.9                           (MPa)                                                                         Energy-break                                                                           33.3   0.87   26.7 0.36 32.7 0.51 23.6 0.37                          (x10.sup.6 J/m.sup.3)                                                         Modulus (MPa)                                                                          107    38.8   126  18.4 99.6 28.7 109  23.2                          ______________________________________                                        % Loss from Dry to Wet                                                        ______________________________________                                        % Strain      86%    90%        90%  91%                                      Peak Stress   75%    83%        77%  78%                                      Energy to Break                                                                             97%    99%        98%  98%                                      Modulus       64%    85%        71%  79%                                      ______________________________________                                    

EXAMPLE 9

A 30/70 weight percent resin blend of low density polyethylene (Dow5031) and poly(ethylene oxide) (WSRN-80) was fed to the Haakecounter-rotating twin screw extruder at a rate of 5 lb/hr.Contemporaneously with the polymer feed to the extruder, specifiedamounts of a monomer, polyethylene glycol ethyl ether (meth)acrylate,and free radical initiator (LUPERSOL 101) were added at the feed throat.The extruder had four heating zones set at 170, 180, 180 and 190 degreesC. The screw speed of the extruder was 150 rpm.

For Example 9 the polyethylene glycol ethyl ether (meth)acrylate feedrate was 0.25 lb/hr and the initiator rate was 0.05 lb/hr.

EXAMPLE 10

A 80/20 weight percent resin blend of low density polyethylene (Dow503I) and poly(ethylene oxide) (WSRN-80) was fed to the Haakecounter-rotating twin screw extruder at a rate of 5 lb/hr.Contemporaneously with the polymer feed to the extruder, specifiedamounts of a monomer, polyethylene glycol ethyl ether (meth)acrylate,and free radical initiator (LUPERSOL 101) were added at the feed throat.The extruder had four heating zones set at 170, 180, 180 and 190 degreesCentigrade (C). The screw speed of the extruder was 150 rpm.

For Example 10 the polyethylene glycol ethyl ether (meth)acrylate feedrate was 0.25 lb/hr (5 weight percent addition) and the initiator ratewas 0.05 lb/hr.

                  TABLE 4                                                         ______________________________________                                                   Example #                                                                     #9              #10                                                             dry    wet        dry  wet                                       ______________________________________                                        Thickness (mil)                                                                            4.2    4.5        4.4  5.2                                       % Strain     260    40         179  150                                       Peak Stress -                                                                              910    30         12   12                                        (MPa)                                                                         % Loss from Dry                                                               to Wet                                                                        % Strain -   85                17%                                            Peak Stress  97                 0%                                            ______________________________________                                    

While the invention has been described with reference to a preferredembodiment, those skilled in the art will appreciate that varioussubstitutions, omissions, changes and modifications may be made withoutdeparting from the spirit hereof. Accordingly, it is intended that theforegoing examples be deemed merely exemplary of the present inventionand not be deemed a limitation thereof.

We claim:
 1. A composition of matter comprising a blend having from about 1 weight percent to about 85 weight percent of a modified polyolefin and from about 99 weight percent to about 15 weight percent of modified poly(ethylene oxide), wherein said modified polyolefin and said modified poly(ethylene oxide) has a total of from about 1 weight percent to about 30 weight percent, based on the total amount of polyolefin and poly(ethylene oxide), of a monomer grafted thereto, wherein said monomer is selected from the group consisting of 2-hydroxyethyl methacrylate and polyethylene glycol ethyl ether (meth)acrylate.
 2. The composition of claim 1 comprising from about 30 weight percent to about 85 weight percent of said modified polyolefin and from about 70 weight percent to about 15 weight percent of said modified poly(ethylene oxide).
 3. The composition of claim 1 comprising from about 55 weight percent to about 85 weight percent of said modified polyolefin and from about 45 weight percent to about 15 weight percent of said modified poly(ethylene oxide).
 4. The composition of claim 1 wherein said polyolefin is polyethylene.
 5. The composition of claim 1 wherein said polyolefin is polypropylene.
 6. The composition of claim 1 wherein said modified polyolefin and said modified poly(ethylene oxide) has a total of from about 1 weight percent to about 20 weight percent of said monomer grafted thereto.
 7. The composition of claim 1 wherein said modified polyolefin and said modified poly(ethylene oxide) has a total of from about 1 weight percent to about 10 weight percent of said monomer grafted thereto.
 8. The composition of matter of claim 1, wherein said monomer is 2-hydroxyethyl methacrylate.
 9. The composition of matter of claim 1, wherein said monomer is polyethylene glycol ethyl ether (meth)acrylate.
 10. The composition of matter of claim 9, wherein said monomer is polyethylene glycol ethyl ether methacrylate.
 11. The composition of matter of claim 1, wherein said polyolefin is a saturated ethylene polymer.
 12. The composition of matter of claim 1, wherein said polyolefin is a homopolymer or copolymer of ethylene or propylene.
 13. The composition of matter of claim 1, wherein said polyolefin is selected from the group consisting of ultra high molecular weight polyethylene, high density polyethylene, ultra low density polyethylene, linear low density polyethylene and polypropylene.
 14. A composition of matter comprising a blend of from about 1 weight percent to about 85 weight percent polyolefin and from about 15 weight percent to about 99 weight percent poly(ethylene oxide), wherein said polyolefin and said poly(ethylene oxide) have from about 1 weight percent to about 30 weight percent, based on the total weight of polyolefin and poly(ethylene oxide), of 2-hydroxyethyl methacrylate or polyethylene glycol ethyl ether methacrylate grafted thereto.
 15. The composition of matter of claim 14, comprising from about 30 weight percent to about 85 weight percent of said modified polyolefin and from about 15 weight percent to about 70 weight percent modified poly(ethylene oxide).
 16. The composition of matter of claim 15, comprising from about 55 weight percent to about 85 weight percent of said modified polyolefin and from about 15 weight percent to about 45 weight percent modified poly(ethylene oxide).
 17. The composition of matter of claim 14, wherein said modified polyolefin and said modified poly(ethylene oxide) have a total of from about 1 weight percent to about 20 weight percent of said monomer grafted thereto.
 18. The composition of matter of claim 17, wherein said modified polyolefin and said modified poly(ethylene oxide) have a total of from about 1 weight percent to about 10 weight percent of said monomer grafted thereto.
 19. The composition of matter of claim 14, wherein said monomer is 2-hydroxyethyl methacrylate.
 20. The composition of matter of claim 14, wherein said monomer is polyethylene glycol ethyl ether methacrylate. 